57.17. pg_prepared_xacts #
 The view pg_prepared_xacts displays information about transactions that are currently prepared for two-phase commit (see PREPARE TRANSACTION for details). 
pg_prepared_xacts contains one row per prepared transaction. An entry is removed when the transaction is committed or rolled back. 
Table 57.17. pg_prepared_xacts Columns
Column Type Description  | 
|---|
 Numeric transaction identifier of the prepared transaction  | 
 Global transaction identifier that was assigned to the transaction  | 
 Time at which the transaction was prepared for commit  | 
 Name of the user that executed the transaction  | 
 Name of the database in which the transaction was executed  | 
 State of the three-phase commit (used only by multimaster)  | 
 When the pg_prepared_xacts view is accessed, the internal transaction manager data structures are momentarily locked, and a copy is made for the view to display. This ensures that the view produces a consistent set of results, while not blocking normal operations longer than necessary. Nonetheless there could be some impact on database performance if this view is frequently accessed.